Confined cell structures and methods of forming confined cell structures

ABSTRACT

Techniques for reducing damage in memory cells are provided. Memory cell structures are typically formed using dry etch and/or planarization processes which damage certain regions of the memory cell structure. In one or more embodiments, certain regions of the cell structure may be sensitive to damage. For example, the free magnetic region in magnetic memory cell structures may be susceptible to demagnetization. Such regions may be substantially confined by barrier materials during the formation of the memory cell structure, such that the edges of such regions are protected from damaging processes. Furthermore, in some embodiments, a memory cell structure is formed and confined within a recess in dielectric material.

BACKGROUND

1. Field of Invention

Embodiments of the invention relate generally to memory, and moreparticularly, to techniques for reducing edge damage in magnetic memorycells.

2. Description of Related Art

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light and not as admissions of prior art.

Magnetic Random Access Memory (MRAM) is a non-volatile memory technologybased on magnetoresistance. Unlike typical Random Access Memory (RAM)technologies which store data as electric charge, MRAM data is stored bymagnetoresistive elements. Generally, the magnetoresistive elements inan MRAM cell are made from two magnetic regions, each of which holds amagnetization. The magnetization of one region (the “pinned region”) isfixed in its magnetic orientation, and the magnetization of the otherregion (the “free region”) can be changed by an external magnetic fieldgenerated by a programming current. Thus, the magnetic field of theprogramming current can cause the magnetic orientations of the twomagnetic regions to be either parallel, giving a lower electricalresistance across the magnetoresistive elements (“0” state), orantiparallel, giving a higher electrical resistance across themagnetoresistive elements (“1” state) of the MRAM cell. The switching ofthe magnetic orientation of the free region and the resulting high orlow resistance states across the magnetoresistive elements provide forthe write and read operations of the typical MRAM cell.

A spin torque transfer MRAM (STT-MRAM) cell is another type of memorycell which is programmed by changing the magnetization ofmagnetoresistive elements. The STT-MRAM cell is written by transmittinga programming current through a magnetic cell stack including a freeregion and a pinned region. The programming current is polarized by thepinned region to have a spin torque. The spin-polarized current thenexerts the torque on the free region, switching the magnetization of thefree region. The magnetization of the free region can be aligned to beeither parallel or antiparallel to the pinned region, and the resistancestate across the stack is changed.

The manufacture of conventional memory cells, including MRAM cells andSTT-MRAM cells, may involve a series of steps to form the differentregions (e.g., the pinned region, the free region, insulating orconductive regions, etc.) of the cell. However, in typical manufacturingtechniques, certain steps may cause damage to the cell structure. Forexample, dry etching may result in demagnetization of the free region,which may affect the programmability of the magnetic memory cell.Furthermore, as cell structures are manufactured to be increasinglysmall in size, the effects of such damage may be more detrimental to thefunction of the cell.

BRIEF DESCRIPTION OF DRAWINGS

Certain embodiments are described in the following detailed descriptionand in reference to the drawings in which:

FIG. 1 is an illustration of an STT-MRAM cell structure, in accordancewith an embodiment of the present technique;

FIG. 2 is an illustration of an STT-MRAM cell structure having edgedamage;

FIGS. 3A-3J illustrate a series of side views and corresponding topviews of one technique for forming an STT-MRAM cell structure havingreduced edge damage, in accordance with embodiments of the presenttechnique;

FIG. 4 is a side view of the STT-MRAM cell structure formed using thetechnique illustrated in FIG. 3, in accordance with embodiments of thepresent technique;

FIG. 5 is a three-dimensional view of the STT-MRAM cell structureillustrated in FIG. 4, in accordance with embodiments of the presenttechnique;

FIGS. 6A-6H illustrate a series of side views and corresponding topviews of a technique for forming an STT-MRAM cell having reduced edgedamage using spacer regions, in accordance with embodiments of thepresent technique;

FIG. 7 is a side view of the STT-MRAM cell structure formed using thetechnique illustrated in FIG. 6, in accordance with embodiments of thepresent technique;

FIGS. 8A-8J illustrate a series of side views and corresponding topviews of a technique for forming an STT-MRAM cell having reduced edgedamage using vias, in accordance with embodiments of the presenttechnique;

FIG. 9 is a side view of the STT-MRAM cell structure formed using thetechnique illustrated in FIG. 8, in accordance with embodiments of thepresent technique; and

FIG. 10 is a side view of another STT-MRAM cell structure formed usingthe technique illustrated in FIG. 8, in accordance with embodiments ofthe present technique.

DETAILED DESCRIPTION

A magnetic memory cell is typically programmed by changing a magneticresistance in the cell. For example, a magnetic memory cell, referred toherein as a cell, may include regions of magnetic materials. Duringprogramming, one magnetic region of the cell, referred to as the “freeregion,” may be switched in magnetization, and another magnetic region,referred to as the “pinned region,” may remain fixed in magnetization.Typically, the free region magnetization may be switched between twoopposite directions to be either parallel or antiparallel to the pinnedregion magnetization. When the magnetizations of the free and pinnedregions are parallel, the resistance across the regions may be low, andwhen the magnetizations of the free and pinned regions are antiparallel,the resistance across the regions may be high. Thus, a magnetic memorycell may be programmed to either a low or a high resistance state byswitching the magnetization of the free region.

One example of such a magnetic memory cell is a spin torque transfermagnetic random access memory (STT-MRAM) cell. A programmable structureof the STT-MRAM cell, referred to as a cell structure 10, is illustratedin FIG. 1. The cell structure 10 may include a free region 14 which maybe switched in magnetization to be either parallel or anti-parallel tothe magnetization of the pinned region 18. In some embodiments, the freeregion 14 and the pinned region 18 may include the same or differentmaterials. For example, each of the free and pinned regions 14 and 18may include magnetic materials or ferromagnetic materials such as Co,Fe, Ni or its alloys, NiFe, CoFe, CoNiFe, or doped alloys CoX, CoFeX,CoNiFeX (X═B, Cu, Re, Ru, Rh, Hf, Pd, Pt, C), or other half-metallicferromagnetic material such as Fe₃O₄, CrO₂, NiMnSb, PtMnSb, and BiFeO,or any combination of the above materials.

The free region 14 and the pinned region 18 may have a barrier region 16in between, which may be suitable for separating the free and pinnedregions 14 and 18 and substantially preventing coupling between themagnetizations of the two regions 14 and 18. For example, the barrierregion 16 may include conductive, nonmagnetic materials such as Cu, Au,Ta, Ag, CuPt, CuMn, nonconductive, nonmagnetic materials such asAl_(x)O_(y), MgO_(x), AlN_(x), SiN_(x), CaO_(x), NiO_(x), HfO_(x),Ta_(x)O_(y), ZrO_(x), NiMnO_(x), MgF_(x), SiC, SiO_(x), SiO_(x)N_(y), orany combination of the above materials. The cell structure 10 may alsoinclude an antiferromagnetic region 20 suitable for fixing themagnetization of the pinned region 18 through exchange coupling, therebyincreasing cell stability.

During a write operation of an STT-MRAM cell, a programming current isapplied to the cell structure 10 of the cell that is selected forprogramming. To initiate the write operation, a write current may begenerated and passed through a data line, which may each be connected toa top lead 12 or a bottom lead 22 of the cell 10. The top lead 12 andthe bottom lead 22 may include conductive materials such as copper andpalladium, for example. In some embodiments, the top lead 12 and bottomlead 22 may each be connected to a data/sense line, for example a bitline of the memory cell, such that a programming current may betransmitted longitudinally through the regions of the cell structure 10.As the programming current passes from the bottom lead 22 to the pinnedregion 18 of the cell structure 10, the electrons of the programmingcurrent are spin-polarized by the pinned region 18 to exert a torque onthe free region 14, which switches the magnetization of the free region14 to “write to” or “program” the cell.

In a read operation of the STT-MRAM cell, a current is used to detectthe programmed state by measuring the resistance through the cellstructure 10. To initiate a read operation, a read current may begenerated and passed from a data line through the cell structure 10,from the top lead 12 to the bottom lead 22 (or from the bottom lead 22to the top lead 12, in some embodiments). The voltage difference betweenthe data lines may be different depending on the resistance through thecell structure 10, thus indicating the programmed state of the STT-MRAMcell. In some embodiments, the voltage difference may be compared to areference and amplified by a sense amplifier.

Therefore, a memory cell such as an STT-MRAM cell may have multipleregions, including at least a free region 14 and a pinned region 18arranged such that a programming current can program the cell and read aresistance through the cell structure 10. Typically, such cellstructures are manufactured using a series of steps including depositingmaterials, planarizing deposited materials to form regions in the cellstructure, and dry etching the materials to form cell structures havinga certain dimension (e.g., having a diameter of 100 nm). However, dryetch processes may damage the edges of the cell structure, which mayresult in the demagnetization of the free region and/or the pinnedregion, the generation of electron spin scattering centers, and/orshortages across cell structure. Moreover, as cell structures areincreasingly manufactured to be smaller in size (e.g., having a diameterof 50 nm or less), the damage to the edges of the cell structure may beeven more detrimental to the performance of the magnetic memory cell dueto the larger surface-area-to-volume ratio of the cell structure. Anillustration of edge damage is provided in FIG. 2, where the hatchedregion surrounding the perimeter of the cell structure 10 representsdamaged regions 24.

In one or more embodiments, the cell structure 10 may be formed withreduced edge damage (also referred to as etch damage). In the techniquesand cell structures illustrated in FIGS. 3-10, certain damagingprocesses such as dry etching or planarizing may be eliminated, and insome embodiments, sensitive regions or materials (e.g., the free region14) may be separated from damaging processes to substantially limitpotential demagnetization in the magnetic materials. Though thetechniques and cell structures illustrated in FIGS. 3-10 generally applyto STT-MRAM cell structures, it should be noted that STT-MRAM cells aremerely an example of one or more embodiments. The present techniques mayapply to any type of magnetic memory cell having magnetic materialssusceptible to demagnetization due to edge damage. Additionally, someembodiments, as described with respect to FIGS. 3-10, may apply to anymemory cell structure, or to any structure having regions of materialswhich may be sensitive to edge damage.

Beginning first with FIGS. 3A-3J, an embodiment for forming a cellstructure without dry etching the edges of the free layer 14 isdescribed. The process steps are represented by structures 30, 32, 34,36, and 38, which illustrate side views (labeled 30 a, 32 a, 34 a, 36 a,and 38 a) and corresponding top views (labeled 30 b, 32 b, 34 b, 36 b,and 38 b) of intermediate structures (referred to as structures) in theformation of two confined STT-MRAM cell structures in a dielectricmaterial. The process described utilizes two cells for simplification ofthe process. Any number of cells can be formed from the describedprocess. As used herein, confined STT-MRAM cell structures may refer toSTT-MRAM cell structures having at least a free region formed in arecess, cavity, via, etc. in dielectric materials. The process beginswith forming the bottom lead 22 in a substrate 26, as illustrated inview 30 a (FIG. 3A). The substrate 26 may include dielectric material(and may also be referred to as the dielectric 26) or any other suitablematerial for separating different cell structures. In one embodiment, aphotolithography and dry etch process may be used to recess thedielectric 26, and conductive materials, such as copper or palladium,may be deposited to form the bottom lead 22 in the recesses of thedielectric 26. For example, a patterned mask may be used to form thedimensions of the bottom leads 22 and arrange the bottom leads in adielectric substrate 26. As indicated in view 30 b (FIG. 3B), the bottomleads 22 may be oval in the dielectric material 26, though differentembodiments may include various shapes.

As illustrated in FIGS. 3C and 3D, the process may then involve etchingthe bottom lead 22 to recess the bottom lead 22 to a certain height inthe recess, as in structure 32 a. The etching of the bottom lead 22material may be via wet etch or other etch processes known in the art.Antiferromagnetic materials are then deposited in the recess to form anantiferromagnetic region 20, and magnetic materials are deposited overthe antiferromagnetic region 20 to form the pinned region 18. Asdiscussed, the pinned region 18 may have a fixed magnetization achievedthrough exchange coupling with the antiferromagnetic region 20. In someembodiments, the antiferromagnetic materials and the magnetic materialsare deposited to form the antiferromagnetic region 20 and the pinnedregion 18. Each may be directionally deposited, such that the regions 20and 18 are formed in one direction. For example, the antiferromagneticregion 20 and the pinned region 18 may be formed on horizontal surfaces(e.g., in a lateral direction), and may not be deposited on the verticalsidewalls 28 (e.g., in a longitudinal direction). In some embodiments, awet etch may be applied after the deposition of the magnetic materialsforming the pinned region 18 to remove excess materials (e.g., materialsdeposited on the vertical sidewalls 28). Excess materials 31 (e.g.,antiferromagnetic materials and magnetic materials) may also be formedover the dielectric 26 and may be removed at a later step in theprocess. The top view of the structure 32 b illustrates the pinnedregion 18 visible in the recesses.

Barrier materials are then deposited into the recess to form a barrierregion 16 in the structure 34 a (FIG. 3E). The barrier materials mayinclude nonconductive, nonmagnetic materials such as Al_(x)O_(y),MgO_(x), AlN_(x), SiN_(x), CaO_(x), NiO_(x), HfO_(x), Ta_(x)O_(y),ZrO_(x), NiMnO_(x), MgF_(x), SiC, SiO_(x), SiO_(x)N_(y), or anycombination of the above materials. The barrier materials may besuitable for physically separating the pinned region 18 from a freeregion 14 and for substantially preventing magnetic coupling effectsbetween the pinned region 18 and the free region 14. In someembodiments, the barrier region 16 may be formed by conformaldeposition, which result in a barrier region 16 disposed over a topsurface of the pinned region 18 and over the vertical sidewalls 28 ofthe recess. In other embodiments, the barrier region 16 may be formed bydirectional deposition, or any other types or combinations ofdepositions methods which result in a barrier region 16 disposed over atop surface of the pinned region 18. As illustrated in the top view ofthe structure 34 b (FIG. 3F), barrier materials 16 may substantiallycover the previously deposited materials.

Magnetic materials are then directionally deposited over the barrierregion 16 to form the free region 14. In some embodiments, a wet etchmay be used to remove any excess materials, including magnetic materialsdeposited on the vertical sidewalls 28. Suitable conductive materialssuch as copper or palladium may then be deposited over the free region14 to form a top lead 12 in the structure 36 a (FIG. 3G). As illustratedin the top view of the structure 36 b (FIG. 3H), the materials of thetop lead 12 may substantially cover the recessed areas, as well as thesubstrate.

As illustrated in structure 36 a (FIG. 3I), excess materials 31 mayinclude one or more of the previously deposited materials, includingantiferromagnetic (from forming the antiferromagnetic region 22),magnetic (from forming the pinned and free regions 18 and 14), barrier(from forming the barrier region 16), and conductive materials (fromforming the top lead 12). Such excess materials 31 may not be useful forfunctioning of the STT-MRAM cell structure 10 a. In some embodiments, aCMP process may be applied to remove the excess materials 31. The CMPprocess may stop at the dielectric material between the formed cellstructures 10 a, and the remaining structure 38 a may include cellstructures 10 a separated by dielectric materials 26. As illustrated inthe top view of the structure 38 b (FIG. 3J), the barrier region 16 mayseparate the top lead 12 from the surrounding dielectric 26.

Therefore, by employing the techniques discussed in FIGS. 3A-3J, dryetching is not used to form the cell structures 10 a. Rather, a seriesof CMPs, depositions, and wet etching may be employed to form recessesfor the cell structures 10 a, deposit various regions, and removeunwanted materials. The remaining cell structures 10 a are contained inthe original recesses and surrounded by the dielectric material 26. Byavoiding techniques such as dry etching, damage to the cell structure 10a, and in particular, damage to the free region 14 and the barrierregion 16, may be reduced. A side view of the completed cell structure10 a formed by the process of FIGS. 3A-3J is provided in FIG. 4.Further, a three-dimensional view of this cell structure 10 a isillustrated in FIG. 5.

Another embodiment for forming cell structures 10 b having reduced edgedamage is provided in FIGS. 6A-6H. FIGS. 6A-6H illustrate a series ofside views (labeled 40 a, 42 a, 44 a, and 46 a) and top views (labeled40 b, 42 b, 44 b, and 46 b) of intermediate structures 40, 42, 44, and46 in forming a cell structure 10 b having a spacer 48. The spacer 48may be configured to reduce an area and/or a volume of the free region14. Typically, the size of a programming current applied to program anSTT-MRAM cell is directly related to the size of the free region 14, asa larger current may be used to switch the magnetization of a largervolume of magnetic material. As such, forming a cell structure with aspacer 48 may result in a smaller free region 14 which may be switchedin magnetization by a smaller programming current.

Similar to the structures 30 and 32 formed in the process of FIGS.3A-3J, the process illustrated in FIGS. 6A-6H may also involve formingrecesses in the dielectric substrate 26 and depositing conductivematerials in the recesses to form the bottom leads 22, as illustrated inthe structure 40 (FIGS. 6A and 6 b). The bottom lead material may thenbe wet etched to form bottom leads 22 having a certain height in therecess, and antiferromagnetic materials and magnetic materials may bedeposited over the bottom leads 22 to form the antiferromagnetic region20 and pinned region 18, as illustrated in the structure 42 (FIGS. 6Cand 6D). The vertical sidewalls 28 may also be wet etched to removeexcess materials.

In some embodiments, nonmagnetic materials such as silicon nitride (SiN)may be deposited to form the spacer region 48 (FIG. 6E). The SiN may bedeposited conformally. The SiN may be dry etched in some embodiments,such that only a region of SiN remains against the sidewalls 28 of thetrench. Although dry etch may be used in this process, the dry etch maynot result in demagnetization of the free region 14 or damage to thebarrier region 16, as the magnetic materials for the free region 14 maybe deposited after the dry etch process which forms the spacer regions48. As illustrated in the top view of the structure 44 b (FIG. 6F), thespacer region 48 may be visible in the cavity and may be formed abovethe exposed pinned region 18.

Once the spacer regions 48 are formed, barrier materials may bedeposited into the recess such that it is disposed over the spacerregion 48 in a vertical (longitudinal) direction and disposed over thepinned region 18 in the horizontal (lateral) direction, forming thebarrier region 16. In different embodiments, the deposition of barriermaterials may be either a conformal or a directional deposition.Magnetic materials may be directionally deposited over the barrierregion 16 to form the free region 14, and conductive materials may bedeposited over the free region 14 to form the top lead 12. In betweendepositions of different materials, a wet etch may be applied to removeexcess materials from the sidewalls 28 of the trench. Furthermore, a CMPprocess may be used to remove excess materials 31 from the top portionsof the dielectric material 26 until the planarization reaches thedielectric 26, which may result in a structure 46 (FIGS. 6G and 6H)having complete cell structures 10 b separated by dielectric 26. Asillustrated in the top view of the structure 46 b, the top lead 12 maybe exposed, and may be surrounded by a barrier region 16, which isfurther surrounded by a spacer region 48 in the recesses of thedielectric 26.

A larger version of the cell structure 10 b formed by the processdiscussed in FIG. 6 is provided in FIG. 7. As shown in FIG. 7, the cellstructure 10 b may include a spacer region 48 surrounding a barrierregion 16 surrounding the free region 14, thus reducing the volume ofthe free region 14 and reducing a programming current which may beapplied to switch the magnetization of the free region 14. It should benoted that although the CMP process removing excess materials 31 isdescribed as stopping on the dielectric material 26 in FIG. 6, the CMPprocess may also instead stop at the barrier region 16, as illustratedin FIG. 7.

Another embodiment for forming cell structures 10 c having reduced edgedamage is provided in FIGS. 8A-8J. FIGS. 8A-8J illustrates a series ofside views (labeled 50 a, 52 a, 54 a, 56 a, and 58 a) and top views(labeled 50 b, 52 b, 54 b, 56 b, and 58 b) of intermediate structures50, 52, 54, 56, and 58 in forming a cell structure 10 c. The process mayinvolve a CMP process and a patterned mask to form recesses in adielectric substrate 26 where materials may be deposited to form cellstructures 10 c. Conductive materials may be deposited in the recessesto form the bottom lead 22, as illustrated in structure 50.

A patterned mask may be used to form the antiferromagnetic region 20 andthe pinned region 18 over the bottom lead 22. Specifically, asrepresented by the structure 52 a (FIG. 8C), the patterned mask may bepositioned such that antiferromagnetic materials may be disposed overthe bottom lead 22 to form the antiferromagnetic region 20, and magneticmaterials may be disposed over the antiferromagnetic region 20 to formthe pinned region 18. As illustrated in the top view of the structure 52b (FIG. 8D), the pinned region 18 may be exposed.

In some embodiments, additional dielectric material 26 may be depositedover the original dielectric material 26 and may cover some portions ofthe pinned region 18, as illustrated in the structure 54 a (FIG. 8E),and an additional mask may be used such that vias 60 are formed in theadditionally deposited dielectric 26. The vias 60 may expose a portionof the pinned region 18. As illustrated in the top view of the structure54 b (FIG. 8F), the via 60 may expose a portion of the pinned region 18while the remaining top surface of the structure 54 includes dielectricmaterial 26.

Barrier materials may then be conformally or directionally depositedover the structure 54 and into the via 60 to form a barrier region 16,such that all surfaces of the via 60 may be covered by the barrierregion 16. The barrier region 16 surrounding the via 60 may also bereferred to as the tunnel barrier and may have a U-shaped or cup shapedstructure. Magnetic materials may be deposited over the structure 54 andonto the tunnel barrier to form the free region 14, as illustrated inthe structure 56 a (FIG. 8G). As illustrated in the top view of thestructure 56 b (FIG. 8H), the top of the structure 56 (including therecesses and the surrounding dielectric 26) may be covered by themagnetic materials deposited for forming the free region 14.

In some embodiments, a CMP process may be used to planarize thematerials deposited for the free region 14, such that the volume of thefree region 14 is substantially contained in the via 60 surrounded bythe barrier region 16 in each cell structure 10 c. Suitable conductivematerials may be deposited to form the top lead 12, as illustrated inthe structure 58 a (FIG. 8I). In some embodiments, theZ originalpatterned mask used to recess the dielectric may be used to form the toplead 12, or in other embodiments, a different mask or no mask may beused. The top view of the structure 58 b (FIG. 8J) depicts the top lead12 configured to be the data line (or to be connected to the data line)of the cell structure 10 c.

A larger version of the cell structure 10 c formed by the processdiscussed in FIG. 8 is provided in FIG. 9. As shown in FIG. 9, the freeregion 14 is substantially contained in between the tunnel barrier ofthe barrier region 16 and the top lead 12. Although portions of the cellstructure 10 c are formed over the bottom lead 22 and are not completelyconfined, any dry etch or CMP processes may not substantially affect thecontained free region 14. Therefore, the free region 14 may be protectedfrom etch damage and may not lose magnetization.

A similar process as that described in FIGS. 8A-8J may be used to obtainthe cell structure 10 d illustrated in FIG. 10. The cell structure 10 dmay be formed by depositing magnetic materials to form a thinner freeregion 14 on the barrier region 16. Suitable conductive materials may bedeposited in the remaining portions of the via 60, over the free region14. In such an embodiment, a smaller programming current appliedvertically through the cell structure 10 d may program the smallervolume of the free region 14 (e.g., in comparison to the volume of thefree region in the cell structure 10 c).

Various embodiments of reducing damage to memory cells are provided, andembodiments are not limited to those illustrated in FIGS. 3-10. Inaccordance with the present techniques, embodiments may includeprocesses for forming memory cells such that certain regions, such asthe free region 14, such that etch or planarization damages may bereduced in those regions. By reducing damage to certain regions whichmay be more susceptible to damage or regions which may adversely affectthe functioning of the memory cell if damaged, cell stability andfunctionality may be maintained. Specifically, techniques for reducingdamage to such regions include forming the cell structure 10 in acontained recess such that etching of the edges may not be necessary orforming the cell structure 10 such that the certain regions (e.g., thefree region 14) are protected from etching, planarizing, or otherdamaging processes.

Furthermore, it should be noted that while the embodiments illustratedin FIGS. 4, 5, 7, 9, and 10 depict a magnetization orientation asparallel to the plane of the substrate in which the cell structure 10 isformed, the present techniques are not limited to any particularmagnetization orientation. In some embodiments, the magnetizationorientation of the free region 14 and pinned region 18 may be in adifferent direction (e.g., perpendicular) compared to the depictedmagnetization orientations in FIGS. 4, 5, 7, 9, and 10. For example, insome embodiments, the free and pinned regions 14 and 18 may have amagnetization orientation that is perpendicular to a plane of the freeand pinned regions 14 and 18 and/or parallel to a direction in which theregions (e.g., regions 12, 14, 16, 18, 20, and 22) are generallydeposited. In such embodiments, the free region 14 may similarly beprogrammed to be parallel or antiparallel to the pinned region 18,indicating different programmed states of the memory cell.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

1. A method for forming a cell structure, the method comprising: forminga recess in a substrate; depositing conductive materials in the recess;recessing the conductive materials to partially fill a bottom of therecess to form a bottom lead that is substantially planar to the bottomof the recess; forming a pinned region over the bottom lead; forming abarrier region within the recess over the pinned region and alongsidewalls of the recess; and forming a free region in the recess andover the barrier region.
 2. The method of claim 1, wherein the cellstructure is substantially confined in the recess.
 3. The method ofclaim 1, wherein the recess is formed by a dry etch or a wet etchprocess.
 4. The method of claim 1, comprising using one common mask toform the cell structure.
 5. The method of claim 1, comprising wetetching materials from sidewalls of the recess before forming thebarrier region over the pinned region.
 6. The method of claim 1,comprising depositing antiferromagnetic materials over the bottom leadto form an antiferromagnetic region, wherein the pinned region isdisposed over the antiferromagnetic region.
 7. The method of claim 6,comprising: depositing conductive materials over the free region to forma top lead; and planarizing excess materials to an unrecessed portion ofthe substrate.
 8. The method of claim 1, comprising depositing siliconnitride (SiN) in the recess to form a spacer region directly adjacent toand between the sidewall of the recess and the pinned region.
 9. Themethod of claim 8, wherein the barrier region is formed directlyadjacent to a sidewall of the spacer region and directly in contact withthe top surface of the pinned region.
 10. The method of claim 1, whereinthe cell structure is a magnetic memory cell structure.
 11. A method offorming a confined magnetic memory cell structure, the methodcomprising: forming a pinned region; depositing dielectric materialsover the pinned region; forming a via in the dielectric materials,wherein the via exposes a portion of the pinned region; depositingbarrier materials over the via and over the exposed portion of thepinned region to form a tunnel barrier in the via; and forming a freeregion in the tunnel barrier, wherein the free region is substantiallyconfined in sidewalls of the tunnel barrier.
 12. The method of claim 11,wherein the pinned region and the free region each compriseferromagnetic materials.
 13. The method of claim 11, wherein themagnetic memory cell structure comprises layers planar to a lateraldirection and stacked in a longitudinal direction.
 14. The method ofclaim 11, comprising forming an antiferromagnetic region, wherein thepinned region is formed directly disposed over the antiferromagneticregion.
 15. The method of claim 14, wherein the antiferromagnetic regionis positioned to achieve exchange coupling with the pinned region. 16.The method of claim 11, comprising forming a conductive contact directlyover the free region, such that the free region is substantiallyconfined by the tunnel barrier and the conductive contact.
 17. Themethod of claim 16, wherein a portion of the conductive contact is in arecess surrounded by the tunnel barrier.
 18. A memory cell structure,comprising: a pinned region; a free region; and a barrier region havinga horizontal portion and vertical portions, wherein the horizontalportion is formed between the pinned region and the free region, andwherein the vertical portions surround the periphery of the free region.19. The memory cell structure of claim 18, wherein the pinned region andthe free region each comprise Co, Fe, Ni or its alloys, NiFe, CoFe,CoNiFe, CoX, CoFeX, CoNiFeX (X═B, Cu, Re, Ru, Rh, Hf, Pd, Pt, C), Fe₃O₄,CrO₂, NiMnSb and PtMnSb, BiFeO, or some combination of the abovematerials.
 20. The memory cell structure of claim 18, wherein thebarrier region is suitable for physically separating the pinned regionand the free region and suitable for substantially limiting couplingbetween a magnetization of the free region and a magnetization of thepinned region.
 21. The memory cell structure of claim 18, comprising aspacer region disposed around a periphery of the vertical portions ofthe barrier region.
 22. The memory cell structure of claim 21,comprising a contact disposed over the free region, wherein a peripheryof the contact is directly adjacent to a sidewall of the barrier region.23. The memory cell structure of claim 18, wherein the memory cellstructure is suitable for a spin torque transfer magnetic random accessmemory (STT-MRAM) cell.
 24. A method of forming a confined cellstructure, the method comprising: forming a recess within a dielectricmaterial; depositing magnetic materials in the recess to form a pinnedregion; forming a barrier region within the recess, wherein the barrierregion comprises a horizontal portion and vertical portions, and whereinsidewalls of the recess are substantially parallel to the verticalportions of the barrier region; and depositing magnetic materials overthe horizontal portion of the barrier region and within the recess toform a free region of the cell structure, wherein the horizontal portionof the barrier region is between the pinned region and the free region.25. The method of claim 24, comprising forming a spacer region betweenthe sidewalls of the recess and a periphery of the vertical portions ofthe barrier region.
 26. The method of claim 24, wherein the verticalportions of the barrier region is directly adjacent to the sidewalls ofthe recess.